<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript">
			
			var num = 1;
			
			/*
			 * 延时调用，
			 * 隔一段时间以后再执行，而且只会执行一次
			 */
			var timer = setTimeout(function(){
				console.log(num++);
			},3000);
			
			clearTimeout(timer);
			
		</script>
	</head>
	<body>
	</body>
</html>
